关键词: 四川盆地, 二叠系, 茅口组, 天然气, 勘探

Abstract: Maokou Formation is one of the major pay zones of Sichuan Basin, in which there are Yangxin Series and Silurian potential source rock. Cracks, pores, and caves are dominant reservoir space of the Formation. In particular, corrosion caves developed from surface Palaeokarst generated after Dongwu Movement are widely distributed in the Formation. Now 99 wells have been drilled in Luzhou Paleouplift area, with the ratio drilled being 9.94% and even reaching as high as 11.35% thanks to repeated borehole drilling.Without the limit of region and structure, venting thickness ranges from 0.1m to 1.0m, with the maximum reaching 3.95m. Venting also exists in synclines, of which the exploration area is more extensive than that of structural traps. Development shows that it is better to cumulatively produce gas in Palaeokarst reservoirs which are well connected with fractured gas reservoirs. Networks consisting of Palaeokarst pores and caves interweave with networks developed from the connection between Palaeokarst reservoirs and fractured gas reservoirs. The interweaving is the best. So research on seismic reflection data should be intensified to find out such types of network systems.

Key words: Sichuan Basin, Permian, Maokou Formation, natural gas, exploration